U.S. patent application number 11/063890 was filed with the patent office on 2005-09-15 for power supply apparatus for vehicles.
This patent application is currently assigned to DENSO CORPORATION. Invention is credited to Mihara, Takashi.
Application Number | 20050200202 11/063890 |
Document ID | / |
Family ID | 34918399 |
Filed Date | 2005-09-15 |
United States Patent
Application |
20050200202 |
Kind Code |
A1 |
Mihara, Takashi |
September 15, 2005 |
Power supply apparatus for vehicles
Abstract
A power supply for vehicles comprises a rush current limitation
circuit, a booster circuit, a backup power supply circuit, a first
wire harness and a second wire harness. An airbag control ECU is
connected to the first wire harness. An engine control ECU, an
electrically-driven power steering control ECU, an air-conditioning
control ECU and a brake control ECU are connected to the second
wire harness. Thus, only one power supply circuit common to the
individual vehicle control apparatus is employed in a vehicle so
that a vehicle control system comprising a plurality of ECUs can be
made compact while the performance of the system can still be
maintained.
Inventors: |
Mihara, Takashi; (Niwa-gun,
JP) |
Correspondence
Address: |
POSZ LAW GROUP, PLC
12040 SOUTH LAKES DRIVE
SUITE 101
RESTON
VA
20191
US
|
Assignee: |
DENSO CORPORATION
|
Family ID: |
34918399 |
Appl. No.: |
11/063890 |
Filed: |
February 24, 2005 |
Current U.S.
Class: |
307/10.1 |
Current CPC
Class: |
H02J 1/10 20130101; H02J
9/002 20130101; B60L 1/00 20130101; H02M 3/158 20130101 |
Class at
Publication: |
307/010.1 |
International
Class: |
B60L 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 10, 2004 |
JP |
2004-67580 |
Claims
What is claimed is:
1. A vehicle power supply apparatus comprising: a regulated power
supply circuit, connected to a battery, for converting an input
voltage supplied by the battery into a regulated output voltage
having a level different from a level of the input voltage; a
backup power supply circuit electrically charged by the output
voltage generated by the regulated power supply circuit; a first
wire connected to a first electrical load, which operates with a
power supplied from either the regulated power supply circuit or
the backup power supply circuit but at least with a power supplied
from the backup power supply circuit in case the regulated power
supply circuit is unavailable, the first wire having a resistance
resulting in a voltage drop to enable the first electrical load to
operate with the power supplied from the backup power supply
circuit; and a second wire connected to a second electrical load,
which operates with a power supplied from the regulated power
supply circuit.
2. The vehicle power supply apparatus according to claim 1, further
comprising: a rush current limitation circuit, connected between
the battery and the regulated power supply circuit through a
switch, for limiting a rush current, which flows when the switch is
turned on.
3. The vehicle power supply apparatus according to claim 1, wherein
the regulated power supply circuit is a booster circuit for
boosting the input voltage supplied by the battery into a boosted
voltage higher than the level of the input voltage.
4. The vehicle power supply apparatus according to claim 1, wherein
the first electrical load is a vehicle passenger protection
apparatus for protecting passengers of a vehicle.
5. The vehicle power supply apparatus according to claim 1, wherein
the second electrical load is at least one of an internal
combustion engine control apparatus for controlling fuel injections
of an internal combustion engine and ignitions of the engine, an
electrically-driven power steering apparatus for controlling a
motor for generating a force assisting a steering force, a vehicle
air-conditioning apparatus for controlling air-conditioning inside
a vehicle and a vehicle brake apparatus for controlling a braking
operation of the vehicle.
6. The vehicle power supply apparatus according to claim 1,
wherein: the first wire and the second wire are connected in common
to the regulated power supply circuit and the backup power supply
circuit; and the first wire has a smaller resistance than the
second wire.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This patent application is based on and incorporates herein
by reference Japanese Patent Application No. 2004-67580 filed on
Mar. 10, 2004.
FIELD OF THE INVENTION
[0002] The present invention relates to a power supply apparatus
employed in a vehicle for supplying power to a plurality of
electronic control apparatuses mounted on the vehicle.
BACKGROUND OF THE INVENTION
[0003] In recent years, a number of vehicle electronic control
apparatuses are mounted on a vehicle such as an automobile. The
vehicle control apparatuses include an engine control apparatus, an
electrically-driven power steering apparatus, and an airbag
apparatus.
[0004] As a typical engine control apparatus, an apparatus for
controlling an internal combustion engine is disclosed in US
2004/0040535 A1, which correspond to U.S. Pat. No. 6,694,959 and JP
2001-152939A. The apparatus for controlling an internal combustion
engine comprises an ignition drive circuit for driving an ignition
coil, an injection drive circuit for driving a fuel injection
valve, and a booster circuit for boosting the voltage of a battery.
The ignition drive circuit applies a voltage output by the booster
circuit to the ignition coil to generate a spark discharge at an
ignition plug. On the other hand, the injection drive circuit
applies a voltage output by the booster circuit to a drive coil of
a fuel injection valve to open the valve.
[0005] A typical electrically-driven power steering apparatus is
disclosed in JP 2003-267235A. This electrically-driven power
steering apparatus has a booster circuit for boosting the voltage
of a battery or the voltage of an electrically charging generator.
A voltage output by the booster circuit is applied to a motor
driving circuit for driving a motor to generate a driving
force.
[0006] As a typical airbag apparatus, a vehicle-passenger
protection system is disclosed in U.S. Pat. No. 6,147,417 (JP
11-245762A). The vehicle passenger protection system comprises a
booster circuit for boosting the voltage of a battery and a backup
circuit, which is electrically charged by the voltage of the
battery and a voltage output by the booster circuit. A voltage
generated by the backup circuit is applied to a squib by way of a
drive circuit, causing an activation current to flow to the squib
and ignite the squib.
[0007] These vehicle control apparatuses each require a booster
circuit having the same function and a power supply circuit such as
a backup circuit. Therefore a vehicle control system cannot be made
compact when the vehicle control system is to be designed as a
system comprising a plurality of vehicle control apparatuses.
SUMMARY OF THE INVENTION
[0008] It is thus an object of the present invention, which
addresses the above problem, to provide a vehicle power supply
apparatus allowing a vehicle control system comprising a plurality
of vehicle electronic control apparatuses to be made compact while
maintaining the performance of the system by employing a power
supply circuit common to the individual vehicle control
apparatus.
[0009] In accordance with a vehicle power supply apparatus
according to the present invention, power is supplied to a first
electrical load at least from a backup power supply circuit to
operate the first electrical load. On the other hand, power is
supplied to a second electrical load from a regulated power supply
circuit to operate the second electrical load. In addition, the
power is supplied to the first electrical load from the backup
power supply circuit through a first wire, which assures that a
voltage enabling the first electrical load to operate is applied to
the first electrical load with a high degree of reliability. It is
thus no longer necessary to provide power supply circuits
separately for the individual first and second electrical loads.
The system comprising the first and second electrical loads
including the vehicle power supply apparatus can be made
compact.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above and other objects, features and advantages of the
present invention will become more apparent from the following
detailed description made with reference to the accompanying the
single drawing FIGURE, which is a circuit diagram showing a vehicle
power supply apparatus according to an embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] Referring first to FIG. 1, a vehicle power supply apparatus
1 comprises a rush current limitation circuit 2, a booster circuit
(regulated power supply circuit) 3, a backup power supply circuit
4, a first wire harness (first wire) 5, and a second wire harness
(second wire) 6.
[0012] The rush current limitation circuit 2 is a circuit for
limiting a rush current, which flows when an ignition switch 7 is
turned on for vehicle operation. The rush current limitation
circuit 2 includes a rush current limitation resistor 2a. One end
of the rush current limitation resistor 2a is connected to the
ignition switch 7, which is connected to the positive electrode
terminal of a battery 8 having a typical output voltage of 12V. The
negative electrode terminal of the battery 8 is connected to the
vehicle chassis. The other end of the rush current limitation
resistor 2a is connected to the booster circuit 3.
[0013] The booster circuit 3 is a circuit for receiving the voltage
output by the battery 8 through the ignition switch 7 and boosting
the voltage to a higher level voltage required by a plurality of
ECUs (electronic control units) 9 and 10a to 10d. The plurality of
ECUs may include an airbag control ECU, an engine control ECU and a
power steering control ECU. The high level voltage is higher than
the voltage output by the battery 8. The booster circuit 3
comprises an input voltage smoothing capacitor 3a, a choke coil 3b,
a diode 3c, an output voltage smoothing capacitor 3d, a field
effect transistor 3e, a transistor driving circuit 3f and a current
detection resistor 3g.
[0014] The input voltage smoothing capacitor 3a is a component for
receiving the voltage output by the battery 8 through the rush
current limitation resistor 2a and smoothing the voltage. One
terminal of the input voltage smoothing capacitor 3a is connected
to the other end of the rush current limitation resistor 2a, and
the other terminal of the input voltage smoothing capacitor 3a is
connected to the vehicle chassis.
[0015] The choke coil 3b is a component for accumulating and
discharging magnetic energy to induce a voltage. One end of the
choke coil 3b is connected to the connection point of the rush
current limitation resistor 2a and the input voltage smoothing
capacitor 3a, whereas the other end of the choke coil 3b is
connected to the anode of the diode 3c. The cathode of the diode 3c
is connected to one end of the output voltage smoothing capacitor
3d and the backup power supply circuit 4. The other end of the
output voltage smoothing capacitor 3d is connected to the vehicle
chassis.
[0016] The field effect transistor 3e is a switching device for
controlling a current flowing through the choke coil 3b. The drain
of the field effect transistor 3e is connected to the connection
point of the choke coil 3b and the diode 3c whereas the gate of the
field effect transistor 3e is connected to the transistor driving
circuit 3f. The source of the field effect transistor 3e is
connected to the vehicle chassis through the current detection
resistor 3g.
[0017] The transistor driving circuit 3f is a circuit for
outputting a drive signal for switching the field effect transistor
3e. An input terminal of the transistor driving circuit 3f is
connected to the connection point of the source of the field effect
transistor 3e and the current detection resistor 3g. Another input
terminal of the transistor driving circuit 3f is connected to the
connection point of the cathode of the diode 3c and the output
voltage smoothing capacitor 3d. The output terminal of the
transistor driving circuit 3f is connected to the gate of the field
effect transistor 3e.
[0018] The backup power supply circuit 4 is a circuit, which serves
as a substitute for the booster circuit 3, supplying a voltage to
the ECUs 9 and 10a to 10d for a short period of time when the
booster circuit 3 is no longer capable of supplying the high
voltage to the ECUs 9 and 10a to 10d. The backup power supply
circuit 4 comprises a charging current limitation resistor 4a, a
backup capacitor 4b and a diode 4c.
[0019] One end of the charging current limitation resistor 4a is
connected to a connection point of the diode 3c and the output
voltage smoothing capacitor 3d, whereas the other end of the
charging current limitation resistor 4a is connected to one end of
the backup capacitor 4b. The other end of the backup capacitor 4b
is connected to the vehicle chassis. The anode of the diode 4c is
connected to the connection point of the charging current
limitation resistor 4a and the backup capacitor 4b, whereas the
cathode of the diode 4c is connected to the one end of the charging
current limitation resistor 4a.
[0020] The first wire harness 5 is a short length and large
diameter lead conductor thus having a low resistance. The first
wire harness 5 connects the booster circuit 3 and the backup power
supply circuit 4 to the airbag control ECU 9. As will be described
later, the airbag control ECU 9 operates by being driven by the
high voltage supplied from the booster circuit 3 or the backup
power supply circuit 4.
[0021] One end of the first wire harness 5 is connected to the
connection point of the cathode of the diode 3c, the charging
current limitation resistor 4a, and the cathode of the diode 4c.
The other end of the first wire harness 5 is connected to the
airbag control ECU 9, which is provided at a location close to the
vehicle power supply apparatus 1.
[0022] The airbag control ECU 9 operates by being driven by the
high voltage supplied from the booster circuit 3 to control the
airbag for protecting passengers in the event of a collision of
the. Even when a terminal of the battery 8 is disconnected due to a
collision of the vehicle, the airbag control ECU 9 is still
maintained operable with the high voltage supplied from the backup
power supply circuit 4 to control the airbag for protecting
passengers.
[0023] The second wire harness 6 is wires for connecting the
booster circuit 3 to an engine control ECU 10a, an
electrically-driven power steering control ECU 10b, an
air-conditioning control ECU 10c and a brake control ECU 10d, which
each operate by being driven by the high voltage supplied from the
booster circuit 3. Unlike the first wire harness 5, however, the
second wire harness 6 does not have to be a wire harness having a
low resistance. That is, the semiconductor diameter and length of
the second wire harness 6 can each be set at such a large value
that a sufficient voltage is still supplied to the engine control
ECU 10a, the electrically-driven power steering control ECU 10b,
the air-conditioning control ECU 10c and the brake control ECU
10d.
[0024] One end of the first wire harness 6 is connected to the
connection point of the cathode of the diode 3c, the charging
current limitation resistor 4a and the cathode of the diode 4c. The
other end of the second wire harness 6 is connected to the engine
control ECU 10a, the electrically-driven power steering control ECU
10b, the air-conditioning control ECU 10c and the brake control ECU
10d.
[0025] As described above, the engine control ECU 10a operates by
being driven by the high voltage supplied from the booster circuit
3 to control fuel injections of the engine and its ignitions.
Similarly, the electrically-driven power steering control ECU 10b
also operates by being driven by the high voltage supplied from the
booster circuit 3 to control a motor for generating a force
assisting a steering force. The air-conditioning control ECU 10c
also operates by being driven by the high voltage supplied from the
booster circuit 3 to control air conditioning inside the vehicle.
The brake control ECU 10d operates by being driven by the high
voltage supplied from the booster circuit 3 to control a braking
operation of the vehicle.
[0026] Here, the backup power supply circuit 4 is also capable of
supplying powers to the engine control ECU 10a, the
electrically-driven power steering control ECU 10b, the
air-conditioning control ECU 10c and the brake control ECU 10d. The
power supplied by the backup power supply circuit 4 is normally
unnecessary. However, this power does not cause adverse effects on
operations of the engine control ECU 10a, the electrically-driven
power steering control ECU 10b, the air-conditioning control ECU
10c and the brake control ECU 10d.
[0027] The vehicle power supply apparatus 1 operates as
follows.
[0028] When the ignition switch 7 is turned on, the output voltage
of the battery 8 is supplied to the booster circuit 3 by way of the
rush current limitation resistor 2a. The input voltage smoothing
capacitor 3a in the booster circuit 3 smoothes the voltage output
by the battery 8. Since the rush current limitation resistor 2a is
connected between the input voltage smoothing capacitor 3a and the
battery 8, no large rush current flows to the input voltage
smoothing capacitor 3a at the time the ignition switch 7 is turned
on.
[0029] The smoothed voltage of the battery 8 is supplied to one end
of the choke coil 3b. When the field effect transistor 3e is turned
on, current flows from the choke coil 3b to the current detection
resistor 3g by way of the field effect transistor 3e, causes a
magnetic energy to be accumulated in the choke coil 3b. When the
field effect transistor 3e is turned off, the magnetic energy
accumulated in the choke coil 3b is discharged, being accumulated
in the output voltage smoothing capacitor 3d by way of the diode
3c. At that time, since a voltage is induced between the two ends
of the choke coil 3b, the voltage of the output voltage smoothing
capacitor 3d becomes higher than the voltage of the battery 8.
[0030] The current detection resistor 3g converts the current,
which flows to the choke coil 3b when the field effect transistor
3e is turned on, into a voltage and supplies the voltage to the
transistor driving circuit 3f. The voltage of the output voltage
smoothing capacitor 3d is also supplied to the transistor driving
circuit 3f. The transistor driving circuit 3f compares the voltage
of the current detection resistor 3g and the voltage of the output
voltage smoothing capacitor 3d with their respective predetermined
threshold values, and outputs a drive signal for switching on and
off the field effect transistor 3e based on results of the
comparisons.
[0031] The field effect transistor 3e is switched on and off based
on the drive signal output by the transistor driving circuit 3f,
thus causing the booster circuit 3 to boost the voltage of the
battery 8 to a predetermined regulated output voltage, which is
higher than the voltage of the battery 8. The voltage output by the
booster circuit 3 is supplied to the airbag control ECU 9 through
the first wire harness 5. The voltage output by the booster circuit
3 is also supplied to the engine control ECU 10a, the
electrically-driven power steering control ECU 10b, the
air-conditioning control ECU 10c and the brake control ECU 10d
through the second wire harness 6.
[0032] In addition, the voltage output by the booster circuit 3 is
also supplied to the backup capacitor 4b by way of the charging
current limitation resistor 4a. The backup capacitor 4b is
electrically charged due to the voltage output by the booster
circuit 3 to a voltage level equal to the level of the voltage
output by the booster circuit 3.
[0033] The voltage of the backup capacitor 4b is supplied to the
airbag control ECU 9 by way of the diode 4c and the first wire
harness 5. The voltage output by the backup capacitor 4b is also
supplied to the engine control ECU 10a, the electrically-driven
power steering control ECU 10b, the air-conditioning control ECU
10c and the brake control ECU 10d through the diode 4c and the
second wire harness 6.
[0034] In this way, the airbag control ECU 9 operates by being
driven by the voltage supplied from the booster circuit 3 and the
backup power supply circuit 4 to control the airbag for protecting
passengers. In addition, even when a terminal of the battery 8 is
disconnected due to a collision of the vehicle, the airbag control
ECU 9 still operates by being driven by the high voltage supplied
from the backup power supply circuit 4 to control the airbag for
protecting passengers.
[0035] The engine control ECU 10a operates by being driven by the
high voltage supplied from the booster circuit 3 to control fuel
injections of the engine and its ignitions. Similarly, the
electrically-driven power steering control ECU 10b also operates by
being driven by the high voltage supplied from the booster circuit
3 to control the motor for generating the force assisting the
steering force. The air-conditioning control ECU 10c also operates
by being driven by the high voltage supplied from the booster
circuit 3 to control air conditioning inside the vehicle. The brake
control ECU 10d operates by being driven by the high voltage
supplied from the booster circuit 3 to control the braking
operation of the vehicle.
[0036] In accordance with the above embodiment, the booster circuit
3 and the backup power supply circuit 4, which are employed in the
vehicle power supply apparatus 1, supply power to the various
control ECUs 9 and 10a to 10d. Even when the terminal of the
battery 8 is disconnected due to the collision of the vehicles,
each control ECU 9 is still capable of operating with a high degree
of reliability by being driven by the high voltage supplied from
the backup power supply circuit 4. In addition, the booster circuit
3 supplies power to each control ECU.
[0037] Since the backup power supply circuit 4 supplies power to
the airbag control ECU 9 through the first wire harness 5 having a
low resistance, a voltage drop along the first wire harness 5 is
small, so that the backup power supply circuit 4 is capable of
supplying a sufficient voltage to the airbag control ECU 9.
Moreover, since it is not necessary to individually provide a power
supply circuit of similar construction to each of the airbag
control ECU 9, the engine control ECU 10a, the electrically-driven
power steering control ECU 10b, the air-conditioning control ECU
10c and the brake control ECU 10d, the system comprising the ECUs
9, 10a, 10b, 10c and 10d requiring a common vehicle power supply
apparatus can be made compact.
[0038] In addition, the vehicle power supply apparatus 1 employs
the rush current limitation circuit 2 capable of limiting the
magnitude of a rush current, which flows to the booster circuit 3
when the rush current limitation circuit 2 is turned on.
[0039] In the embodiment described above, only the airbag control
ECU 9 is connected to the first wire harness 5 in the vehicle power
supply apparatus 1. It is to be noted, however, the first wire
harness 5 may be connected to other control ECUs as long as such
ECUs each operate by being driven by the high voltage from the
booster circuit 3 and the backup power supply circuit 4.
[0040] In addition, the engine control ECU 10a, the
electrically-driven power steering control ECU 10b, the
air-conditioning control ECU 10c and the brake control ECU 10d are
connected to the second wire harness 6 in the vehicle power supply
apparatus 1. It is to be noted, however, that the second wire may
be connected to other ECUs as long as such ECUs each operate by
being driven by the high voltage from the booster circuit 3.
[0041] Further modification and alteration are also possible
without departing from the spirit of the invention.
* * * * *